Strain-induced ferroelectricity and lattice coupling in BaSnO3 and SrSnO3
Strain-induced ferroelectricity and lattice coupling in BaSnO3 and SrSnO3
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BaSnO3 和 SrSnO3 中的应变诱导铁电和晶格耦合
DOI：
10.1039/c7cp03952b
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发表时间：
2017
影响因子：
3.3
通讯作者：
Kitamura Takayuki
中科院分区：
文献类型：
--
作者：
Zhang Yajun;Wang Jie;Sahoo M. P. K.;Shimada Takahiro;Kitamura Takayuki
BaSnO 3、SrSnO 3等过锡酸盐具有良好的光伏特性，有望应用于太阳能电池。然而，这些材料中铁电性的缺乏和宽带隙限制了它们在光伏应用中的潜力。在这里，通过第一性原理计算，我们证明了实现一个主要的铁电极化在非铁电BaSnO 3和SrSnO 3通过应变工程。除了极化的外观，材料的带隙大大缩小时，顺电铁电相变发生在压缩应变。此外，一个有趣的Q2模式触发晶格耦合与极性模式被发现在受到足够的拉伸应变的锡酸盐和这种模式有显着的影响的带隙，这表明另一种途径来缩小带隙通过电场控制的Q2模式。富有成效的电子，结构和能量特性进行了详细讨论，以实现应变诱导的铁电性，可调带隙，Q2模式和不同的极性/旋转扭曲的钙钛矿锡酸盐之间的晶格耦合的基本理解。
Perovskite stannates such as BaSnO3 and SrSnO3 exhibit promising photovoltaic properties, and hold promise for application in solar cell devices. However, the lack of ferroelectricity and the wide band gap in these materials limit their potential for photovoltaic applications. Here, by first-principles calculations, we demonstrate the realization of a primary ferroelectric polarization in non-ferroelectric BaSnO3 and SrSnO3 through strain engineering. In addition to the appearance of polarization, the band gaps of the materials are greatly narrowed when the paraelectric to ferroelectric phase transition takes place under compressive strain. Furthermore, an intriguing Q2 mode triggered by lattice coupling with the polar mode is found in the stannates subjected to a sufficient tensile strain and this mode has a significant effect on the band gap, which suggests another pathway to narrow the band gap through the electric field control of the Q2 mode. The fruitful electronic, structural, and energetic properties are discussed in detail to achieve a fundamental understanding of the strain-induced ferroelectricity, tunable band gap, and lattice couplings between the Q2 mode and different polar/rotational distortions in the perovskite stannates.